Alcohol addiction is a disease that can negatively affect people's relationships, productivity and can lead to major health problems including death. It is estimated that 17.6 million Americans suffer from alcohol abuse or alcoholism yet there are very few effective treatments available signifying the need to better understand how alcohol affects the mammalian brain. This goal of this proposal is to better understand the molecular mechanisms that mediate alcohol consumption and relapse. It is widely accepted that alcohol consumption leads to neuroadaptive changes in intracellular signaling cascades that regulate neuroplasticity. Brain circuits that contribute to alcohol seeking behaviors are particularly vulnerable and their dysregulation may mediate behavior pathologies associated with alcohol addiction. One brain region of interest is the amygdala, which regulates alcohol reinforcement and reward- related learning. Preliminary data identified the alpha subunit of calcium/calmodulin kinase II (CAMKII) as a calcium-signaling protein kinase that is upregulated in the amygdala following chronic alcohol self- administration in C57BL/6J mice. CAMKII modulates receptor activity and initiates multiple transcription factors that control neural plasticity, yet the functional involvement of CAMKII in alcohol self-administration remains unknown. This project seeks to test the overall hypothesis that CAMKII is increased following alcohol self-administration and that modulating CAMKII activity functionally regulates alcohol-seeking behaviors in three separate but integrated specific aims: 1) to characterize the effect of chronic alcohol self- administration on the CAMKII pathway using western blot and immunohistochemical analysis;2) to examine the effect of operant alcohol self-administration on CAMKII activity and determine if CAMKII functionally regulates the reinforcing effects of alcohol in mice using site-specific infusions of a pharmacological CAMKII inhibitor into the amygdala;and 3) to determine if CAMKII in the amygdala functionally regulates cue- induced reinstatement of alcohol-seeking, a behavioral model of relapse, using site-specific infusions of the CAMKII inhibitor. These preclinical experiments have the potential to reveal a novel molecular mechanism that underlies alcohol reinforcement and relapse, behavioral pathologies that characterize alcohol addiction.